Tool for making electrical connectors



P 1944- v. E. cARLsoN 2,359,083

TOOL FOR MAKING ELECTRICAL CONNECTORS Filed Aug. 17, 1942 2 Sheets-Sheet1 3! INVENTOR K: arr/E arls 11/ BY A'rr RNE.

Patented Sept. 26, 1944:

TOOL

Vernon E. Carlson,

Aircraft-Marine ron mxmc ELECTRICAL CONNECTORS Short Hills, N. J.,assignor to Products, 1110., Elizabeth, N. J.,

a corporation of New Jersey,

Application August 17, 1942, Serial No. 455,033

13 Claims.

This invention relates to a method of closing, crimpin or otherwisecompressing a ferrule or the like and to a crimping or closing tooladapted particularly for closing, crimping, or otherwise compressing theferrule portion of a connecting member onto the insulation of anelectrical conductor.

It has been common practice before my invention to secure ferrules,thimbles, etc. in place by crimping and this has been practiced inparticular in applying terminals to insulated wire by crimping a ferruleor sleeve portion of the terminal after an insulated portion of the wirehas been inserted into it. Such crimping, however, has ordinarilyinvolved the forming of one or more re-entrant folds in the ferrule withthe result that either the insulation is very severely deformed or theferrule is not securely held on and sealed to the Wire.

It is an object of the present invention to provide a simple and directcompression of a. ferrule or like member to reduce its periphery withoutfolding or other severe deformation.

Another object of the invention is to provide for the compression orcrimping of a ferrule or the like by a simple press or hand tool.

Another object of the invention is to provide for crimping a ferruleonto a flexible tube or sheath with production of a final form so closeto a circular form as to avoid injury to a tube or sheath and to assurecontinuous engagement thereof, and of such reduced periphery, as to makea fluid-tight seal thereto.

Another object of the invention is to provide for applying to aninsulated conductor a terminal of the type having an inner ferrule forengaging and contactingthe central conductor and an outer ferrule orsleeve fitted over the inner ferrule and extending therebeyond toreceive and support the end of the insulation on the Wire, and it isalso an object so to compress this extended portion about the insulationas to secure them and seal them together without substantially weakeningor damaging either.

I have discovered that if the ferrule or other article to be crimped isproperly supported during the crimping operation, the pressure may be soexerted peripherally on the ferrule as actually to compress the metaland reduce the peripheral dimension without any sharp folding orcollapsing of the portions crimped. Thus, a portion of the ferrule canbe so constricted onto an insulated wire or other member as to assure aper manent engagement and even a fluid-tight seal thereto.

the pins :2 and 33 In these drawings, I have shown and described apreferred embodiment of my invention and various modifications thereof;but it is to be understood that these are not intended to be exhaustivenor limiting of the invention but on the contraryare given for purposesof illustration in order that others skilled in the art may fullyunderstand the invention and the principles thereof and the manner ofapplying it in practical use so that they may modify and adapt it invarious forms, each as may be best suited to the conditions of aparticular use.

In these drawings, in which like reference characters refer to similarparts:

Figure 1 is a plan view of a novel and improved hand tool embodying theinvention;

Figure 2 is a longitudinal section through a terminal being crimped anda cross section through the tool shown in Figure 1;

Figure 3 is a perspective of the tool of Figure 1 but showing it fromthe other side;.

Figure 4 is a perspective of a crimped terminal;

Figure 5 is a plan view of a modified form of a novel and improved handtool embodying the invention;

Figure 6 is an enlarged sectional view of a portion of the toolillustrated in Figure 5; p Figure 7 is a plan view of a furtherembodiment of the invention; and

Figure 8 is a cross section taken on line 3-8 of Figure 4.

In Figures 1 through 3 I have shown a hand tool designed particularlyfor applying terminal connectors to insulated wire. A pair of handles 20and 2| are indicated pivotally connected to one another by the pin 40,and are normally held opened, 1. e., spread apart, by the spring 4|.Handles 20 and 2|, respectively, are pivoted to jaws 24 and 25 by pins38 and 39. The jaws 24 and 25 are pivoted on an aligning bearing 34 andare pivotally connected together by two links 35, the upper one of whichhas been removedin Figure 1. These links are held to the respectivefaces of the jaws 24 and 25. and pivotally connected to them by pins 32and 33, respectively. The bearing 34, being located in a recess of thejaws 24 and 25, as illustrated, is retained in its proper positionaxially by intermediate portions of links 35.

As handles 20 and 2| are moved toward one another about the axis of pin40 pins 38 and 39 are moved away from one another and with them theadjacent ends of the laws 24 and 25. Since are maintained in apredetermined spaced relationship by links 35, this movement of the endsof jaws 24 and 25 must be a rocking movement, whereby upper portionsthereof are moved toward one another. The

jaws are so designed that, during movement of the handles 28 and 2| andthe resulting movement of jaws 24 and 25, the same bearing relationshipis maintained between jaws 24 and 25 and bearing 34.

The faces 28 and 21 (see Figure 3), respectively, of the jaws 24 and 25meet when handles 28 and 2| are squeezed and thus limit the extent towhich jaws 24 and 25 may be brought together. If desired, the crimpingdies of my present invention may be formed in the jaws 24 and 25adjacent to the faces 28 and 21. As shown, however, these jaws 24 and 25are formed in accordance with the invention of U. A. Whitaker, describedand claimed in a copending application, Serial No. 455,039 filedherewith, t crimp the heavier ferrule 38 onto the central conductor 22of the wire W, while the crimping of the extended sleeve 3| onto theinsulation 23 is performed by overlying die plates 28 and 29. Plate 28is pivoted on jaw 24 by means of pin 32 and plate 29 is pivoted on jaw25 by pin 33. Removable bolts 18 and 19, or other fastening means, fixthe angular relationships between the plates 28 and 29 and the jaws 24and 25, respectively. Different positioning of the plates 28 and/or 29on their jaws to accommodate different sized ferrules or wire isattained by putting the bolt 18 into different holes 18, H or 12 ofplate 28 and bolt I9 into different ones of the holes 13, I4, or 15,since underlying holes in jaws 24 and 25 into which the bolts 18 and I9align, respectively, with the holes 18, 1|, i2, 13, I4, and 15 of plates28 and 29, each give different angular positions of the plates.

Plate 29 is provided with a projection designed to fit into recess 58 ofplate 28 when the two plates are moved toward one another. Likewise,plate 28 is provided with a projection 54 arranged to fit into a recess55 of plate 29 when the plates are moved toward one another. Betweenthese fitted portions on each of the plates 28 and 29 are die surfaces58 and 58, respectively, each'of which is concave between the base ofthe adjoining projection 5| or 54 and the s de of the adjoining recess58 or 55. The arrangement is such that as plates 28 and 29 are movedtoward one another by pressing handles 28 and 2| together, theprojection 5| overlaps plate 28 in the recess 58 and projection 54overlaps the plate 29 in the recess 55 so that a space is enclosedbetween the overlapping portions and the die surfaces 58 and 59. As thedie surfaces 58 and 59 are made further to approach each other thisspace is narrowed and any ferrule or other article engaged in theopening is required to conform itself to this decreasing area andperiphery.

The surfaces of overlapping projection 5| and of the recess 58 are, whenthe space is first enclosed, at an angle to one another and aregradually brought into parallelism and eventually into full contact asthe jaws are closed. This results in a compression of the space betweendie surfaces 58 and 59 in a direction transverse to their closingmotion. Moreover, the ends of the projections 5| and 54 are rounded sothat, if a relatively large ferrule, etc., is being engaged between thedie surfaces 58 and 59, it will first be subjected to a lateralcompression by camming action of these rounded ends even before thespace between them is closed; and the ferrule may thus be compressed soas to fit into said space. After the rounded portion passes the cornerof the opposite die, the ferrule is supported at the edges while it isbeing compressed between the die surfaces 58 and 59. Due to the smooth,concave form of the die surfaces with no re-entrant or projecting partwhich could start an unsupported buckling, the effect of suchcompression is to reduce the periphery by actual compression of themetal, whereas if the metal were once allowed to buckle inwardly or toescape into any gap within the dies, the compressive stress would berelieved and it would merely produce a sharp fold. At these oppositeends the surfaces 58 and 59 are formed with narrow steps 68, BI, 82 and53. Because these are so close to the lateral faces of the projections5| and 54, respectively, any inward folding or buckling which mightotherwise result receives immediate support from the lateral faces andthus cannot relieve the peripheral compressive stress. On the contrarythe provision of these opposed steps enables the opposite dies to gain afirm hold on the lateral portion of the ferrule and subject it to a veryintense local compression. This is clearly shown in Figure 8 wherein thelateral portions 54 and which have been compressed between the steps88-53 and 6|62, respectively, have been appreciably thickened in crosssection as compared with the upper and lower portions of the ferrule.The use of the diamond form instead of a smooth arcuate curve also.helps in attaining the desired compression since the flattening of theferrule wall from its arcuate form to the fiat faces of the diamond formtakes advantage of the high mechanical advantage of a toggle action.This in turn flattens the lateral portions of the ferrule against thedie portions 5| and 54 and assures against buckling or folding offerrule in these portions. I

In order to give a close fit between the projections 5| and 54 and therecesses 58 and 55, the

bearing member 34 may be made slightly smaller than the bearings whichreceive it. Thus, as the jaws are closed together, plates 28 and 29 mayshift slightly along the radius of their movement to allow theprojections to match closely in said recesses.

When the jaws are opened, the projection 5| moves away from the side ofthe crimped ferrule and thus the ferrule is released for easy removalfrom the die.

In Figure 2 the tool is shown in use for applying a terminal connector Cto an insulated wire W. In this use the insulation 23 is first strippedoff for a short distance from the end of the central conductor 22 andonto this end is fitted the terminal connector, the connector shown inthese figures being one more fully described and claimed in copendingapplications, Serial No. 421,408, filed December 3, 1941, and Serial No.459,624, filed September 24, 1942.

This connector consists of a terminal contact portion l9 of standardform, a main ferrule 88 integral therewith, and a longer ferrule orsleeve 3| fitted over the main ferrule and extending beyond it toreceive and support the insulated part of the wire. The ferrule 38 maybe closed or open at the end next to the contact portion 9, and may beseamless or rolled. Also a single, stepped ferrule may be used insteadof the ferrule 38 and overlying sleeve 3|.

A jig I84 attached to one of the jaws, as shown in Figures 2 and 3,receives the contact portion l9 of the terminal into the recessed end ofthe slide I85, which is adjustable in a slot I85 by Tborder will be leftflaring slightly from the crimped section and the crimped sleeve willthus give a smoother support to the insulation with no tendency to cutor break the insulation at the end of the sleeve by repeated flexing. Aflat spring I08 is advantageously used within the recessed end of slideI05. The spring is stiff enough to limit the position of the terminalconnector, but is sufficiently flexible to accommodate the elongation ofthe ferrule which results from crimping and, thus, to avoid anyflattening of the end of the contact portion 19.

.The die surfaces 58 and 59 of plates 28 and 29 are slightly sloped fromthe side on which the jig I04 is mounted and, thus, they provide aslight taper to the crimped portion of a ferrule so that there will be agradual merging from the cylindrical, uncrimped section of the ferruleto the most severely crimped section, as shown in Figure 4. Furthermore,any tendency to sheer the ferrule by sharp concentration of stresses atthe edge of the die during the crimping operation is limited by thetapered configuration presented by the die surfaces.

Although there is much advantage in the par ticular construction shownin Figures 1 to 3, my broad invention may be embodied and practiced withother and simpler structures. Figures 5 and 6 give one illustration ofthis. The modified form of hand tool shown in Figure 5 uses instead ofthe overlapping projections 5| and 54, blocks of rubber or otherdeformable material, and instead of the double lever system shown inFigure 1 the handles a and 2la are integral with jaws a and 24a,respectively, as in pliers construction. The surface of jaw 24a isrecessed at a and a and the opposite jaw 25a is provided with two rubberblocks Ma and 54a set in and projecting from the jaw surface. Blocks Maand 54a are received only partially by recesses 50a and 55a when thejaws are closed so that when the handles are fully squeezed together therubber of these blocks is extruded into a space between them. Betweenthe recesses of jaw 24a and blocks of jaw 25a there are showncylindrically shaped die surfaces 581; and 59a for receiving andcrimping a ferrule. The die surfaces 58a and 59a may be sloped from sideto side, as already described in connection with Figures 1 to 3, or maybe rounded to a minimum diameter near the center of their thickness withgreater diameter at each side.

In the use of this tool, a ferrule which is to be fastened to anelectrical conductor and which has been positioned over the end of anelectrical conductor is positioned between the projections Sla and 54a.Jaws 24a and 25a are then closed tightly upon the ferrule and theferrule is pressed into the space between the die surfaces 58a and 59awhich, being in part at least of smaller diameter than the ferrules,crimp it onto the insulation of the conductor. The portions ofprojections 5m and 54a which are extruded into the space defined by diesurfaces 58a and 59a are exposed to the edges 'of the ferrule, whichwould have to spread laterally if the. ferrule were merely flattened bythe pressure applied. Since, however, there is no place for the rubberto go when the recesses 50a and 55a are fllled except to be squeezedinto the space bounded by die surfaces 58a and 59a and since a ferrulelocated between the die surfaces presents a more yield- 'able mass thanthe jaws which otherwise surround the rubber blocks, the rubberisactually pressed into the ferrule, crimping it and/or supporting itagainst spreading and flattening.

When the jaws are again opened the rubber draws back to its normal formand the ferrule is released for easy removal from the die.

Figur 7 illustrates a section through jaws'llb and 25b of a hand tool ofthe same general type as that illustrated in Figure 1, correspondingparts bearing the same reference numerals with the addition of b. Inthis case, however, the die surfaces 58b and 55b instead of being V-shaped are half round and the die is shown in use for closing, insteadof (or prior to) crimping, a ferrule. I

The die surfaces of each of the embodiments described are so arrangedthat a ferrule compacted therebetween may easily be removed after acompacting operation. The die surfaces are separable so that the crimpedferrule has only to be lifted out of the tool. Because of theoverlapping configurations of the jaws associated with the die surfaces,however, there is no place for the metal of the ferrules to go duringthe compacting operations so that each ferrule is simply compacted,without extruding or folding, into the insulation of the electricalconductor to which it is to be connected. The result is that eachferrule is permanently bonded to the insulation of the electricalconductor with a secure, watertight seal.

The die surfaces of the tool illustrated in Figures 1 to 3 will impressa crimp which is more or less hexagonal in cross section. The toolsillustrated in Figures 5, 6 and 7 will form a crimp more or lesscircular in cross section. In so far as the broad invention is concernedit isimmaterial just what the cross section of a crimp may be. Broadly,the invention encompasses tools wherein, as the die surfaces are broughttogether, the perimeter of the ferrule which is to be crimped is givensupport so that folding or extruding of th ferrule with respect to thedie surfaces is impossible and so that a compressed portion of reduceddimensions results.

From the foregoing it will be seen that crimping devices made inaccordance with the present invention are well adapted to attain theends hereinbefore set forth and to be economically manufactured.

I claim:

1. In apparatus of the class described, a pair of compression dieshaving concave surfaces free from substantially inwardly projectingareas, said dies including means for providing lateral support to workbetween said die surfaces, whereby the work compressed between the diesurfaces is subjected to compressive strains while substantially itsentire periphery is supported against buckling or collapsing, andresilientmeans for freeing the work from the dies after compressiontherebetween, whereby the work may easily be removed therefrom.

2. In apparatus of the class described, a pair of compression dieshaving concave surfaces free from substantially inwardly projectingareas, said dies including means for providing lateral support to workbetween said die surfaces, said means including elastically deformable,incompressible inserts at the sides of said concave die surfaces, andmeans for imposing a compressive force on said inserts whereby to exertthrough them a lateral force against the work under compression betweenthe die surfaces, whereby to aid in reducing the cross sectional areabetween the die surfaces as the dies approach one another.

3. In apparatus of the class described, a pair of compression dieshaving concave surfaces free from substantially inwardly projectingareas, said concave die surfaces being less than semi-circular and saiddies including resilient means for aiding in freeing work therefromafter compression therebetween, whereby work being formed between thedies is readily released when the dies are moved away from one another,and said dies including means for providing lateral support to workbeing formed between said die surfaces, whereby the work may becompressed between the die surfaces with substantially full peripheralsupport against buckling or collapsing.

4. A tool for crimping a ferrule, said tool having opposing jaw membersprovided with die portions for compressing the ferrule, each of said jawmembers including a projecting portion for cooperating with a dieportion to afford a lateral support and at least one of said projectingportions having its edge toward the die portion sloped away from the dieportion along its direction of movement, whereby taproduce a cammingaction on the ferrule as they die portion is moved to apply pressure tothe ferrule, each of said die portions having a shallow V-form and eachof said projecting portions having a substantially fiat surface, wherebywhen said jaw members are opened the compacted ferrule may easily beremoved from the tool.

5. A tool for crimping a ferrule, said tool having opposing jaw membersprovided with concave die surfaces for peripherally compressing theferrule and said jaw members including means extending across the endsof the recess between said concave surfaces and interfitted with theedges of said dies for giving lateral support to the ferrule as it iscompressed by the dies, whereby the ferrule may be compressed withsubstantially full peripheral support against buckling or collapsing,said dies being sloped in a direction parallel to the axis of the die,whereby to give a tapered configuration to the ferrule.

6. A tool for crimping one end of a ferrule, said tool having opposingjaw members provided with concave die surfaces for peripherallycompressing the ferrule, said jaw members including means extendingacross the ends of the recess between said concave surfaces andinterfitted with the edges of said dies for giving lateral support tothe ferrule as it is compressed by the dies, whereby the ferrule may becompressed with substantially full peripheral support against bucklingor collapsing, said dies being sloped in a direction parallel to theaxis of the die, whereby to give a tapered configuration to the die, andone of said jaw members including a jig for positioning and adjustableon said jaws with respect to said stop portions so as to predeterminethe extent of compression to which said ferrule may be subjected by saiddies, differently for different ferrules, said means including aplurality of holes in said die plates and jaws respectively. one pair ofholes being aligned in each adjustment of a die plate on its jaw andlocking pins adapted to be secured in any of said aligned holes, wherebydifferent adjustments may be made selectively by holding different setsof holes in alignment with the looking pins.

8. A tool for compacting a ferrule, said tool having opposing jawmembers provided with concave die portions for compressing the ferrulebetween them and including cooperating, interfitted portions for givingsupport to the ferrule as the die portions approach one another, saidinterfitted portions including at least one rubber element adapted to besqueezed between said jaws and thereby extruded against the ferrule asthe die portions approach one another whereby to counteract the tendencyof the ferrule to extrude or buckle between said dies.

9. A crimping tool of the type having a pair of compression dies eachhaving thereon a concave die face, a projecting portion at one sidethereof provided with a face extending from said concave face, adaptedto form a lateral die face parallel to the path of movement of the dieswhen closed together, and overlapping the side of the other die to closesaid recess, and each die having its other side fitted to saidoverlapping face of the opposite die so as to engage it slidably duringthe final operations of said dies, said tool being characterized by therecess-forming portions of said dies having die surfaces composed of aseries of major faces which substantially surround said recess, each ofsaid faces being oriented with respect to the adjacent major faces atnot substantially more than and said recess being free from any inwardlydirected projection capable of effecting an unsupported buckling of theferrul wall.

10. A crimping'tool as defined in claim 9 in which the die surfacesrespectively are provided with narrow steps close to the lateral diefaces, respectively, whereby lateral portions of the work are engagedbetween said steps and thereby subjected to intense local peripheralcompression.

11. A crimping tool as defined in claim 9 in which the major diesurfaces are substantially planar, whereby closing of the dies imposesintense peripheral compression on the work.

12. A crimping tool as defined in claim 9 in which the major diesurfaces are substantially hexagonally arranged planar faces, wherebyclosing of the dies imposes intense peripheral compression on the work.

13. In apparatus of the class described, a pair of compression dieshaving concave surfaces free from substantially inwardly projectingareas, said dies including means for providing lateral support to workbetween said die surfaces, whereby the work compressed between the diesurfaces is subjected to compressive strains while substantially itsentire periphery is supported against buckling or collapsing; saidapparatus being characterized by the fact that the means for providinglateral support are resiliently, relatively, slightly moveable withrespect to one another, whereby after a compression operation the workmay easily be removed from the dies.

VERNON E. CARLSON.

